che_april-2024 - 14

Stockwell Elastomerics
FIGURE 2. The ability of Stockwell to create more
complex geometries using waterjet cutting, CNC
flash cutting and a variety of 3-D molding capabilities
provides seals and gaskets in more intricate
shapes and provide a better seal without using
multiple gaskets
cated shape, " explains Rimel. " But
recently we've been able to provide
more complex geometries using waterjet
cutting, CNC flash cutting and
a variety of 3-D molding capabilities
[Figure 2]. This allows us to provide
seals and gaskets in more intricate
shapes for applications in controls
equipment, valve actuators and
sensors, and provide a better seal
around a complicated shape without
using multiple gaskets. Because
the ability to provide complex geometries
enables a tight seal using
a continuous piece of material versus
multiple gaskets, which tend to
leave a seam and reduce the reliability
of the seal, it is a game changer in
many applications. "
Innovations meet challenges
While seals can be designed to provide
higher levels of reliability, it is
sometimes still a challenge to find a
seal that not only meets the needs
of the application but also the demands
of the environment in which it
will operate, says Oliver Cann, product
and engineering director with
Vulcan Seals (Sheffield, UK; www.
vulcanseals.com). " A lot of processors
specify seals to suit the direct
application with which they are
working, but there are a lot of other
variables to consider, " he says. " It is
possible that the material that is ideal
for the media doesn't jive with the
temperatures, pressures or cleaning
process, which can make it difficult
to effectively specify a commercially
viable or commercially reasonable
sealing technology that covers all the
application parameters. "
As a solution, Vulcan Seals offers
encapsulated seals in a variety
14
of materials. " Our FEP- (fluorinated
ethylene propylene) and PFA- (perfluoroalkoxy
alkane) encapsulated
seals [Figure 3] are resistant to a
wide range of chemicals and serve
as a universal O-ring that can work
in a variety of applications, " notes
Cann. Vulcan's encapsulated seal
products are O-rings that are bound
by a seamless and uniform FEP/PFA
encapsulation, which encloses an
elastomeric core, completely protecting
it from the media. They combine
the energizing properties of an
elastomeric O-ring with the resilience
to extreme temperature and hostile
chemicals provided by FEP/PFA.
" The rubber creates a unique energy
whereby under compression it
creates load, which is essential for
creating a pressure-tight seal that
is able to block a barrier while also
allowing the use of a highly inert
and chemically resistant material as
the contact barrier, " explains Cann.
" Traditionally a PTFE (polytetrafluoroethylene)
would be the commercially
viable seal material used in
difficult applications, but it doesn't
provide the energy that is achieved
via the rubber elastomer core. Here,
we get the energy needed from the
rubber elastomer, but protect it with
a highly resistant barrier and use a
process to make the encapsulation
around them seamless to provide a
leak-tight seal that resists damage
from chemicals and other process
variables that are common in the
chemical industry. "
Another sealing challenge in the
CPI is the requirement for cleaningin-place
(CIP) and sterilization-inplace
(SIP) regimes. Often, seals that
suit the other aspects of the application
cannot withstand the
demands of these processes,
making it difficult to find a reliable
seal, especially in foodand-beverage
applications.
" The
sealing
environment
for food-and-beverage processing
is one of the most demanding, "
says David Kaley,
global segment manager with
Trelleborg Sealing Solutions
(Trelleborg, Sweden; www.
trelleborg.com). " Seals are essential
to food safety, ensuring
that contaminants do not
come in contact with the food. Seal
failure can lead to potential contamination,
resulting in line stoppages,
recalls or, in the worst case, harm
to consumers. Materials, whether
elastomer or plastic, must cope with
the processing of a broad variety of
food types along with CIP and SIP
regimes, which can quickly destroy
incorrectly specified seals. On top of
this, seals must comply with various
global food contact regulations. "
To provide sealing solutions that
meet the needs of food-and-beverage
processors, Trelleborg offers a
family of EPDM (ethylene propylene
diene monomer) rubber materials,
specifically designed to meet the
unique requirements of the foodand-beverage
industry. Called the
FoodPro EPDMs [Figure 4], the seals
comply with the most comprehensive
global food contact material regulations,
are suitable for use with virtually
all food and beverage products
and can withstand harsh CIP and
SIP processes. They are compression
and injection moldable, which
means they can be used for O-rings,
static seals and engineered molded
parts, and they offer dynamic properties
with improved tensile strength,
reduced elongation and tear and
wear resistance.
'Green' energy applications
Innovation and developments in
sealing technologies come at a time
when they are needed in new applications
surrounding the burgeoning
green energy market.
" Sealing technologies help simplify
energy transition for process
industries, " says Leo Konradsson,
global segment manager, power
Vulcan Seals
FIGURE 3. Vulcan's encapsulated seal products are O-rings
that are bound by a seamless and uniform FEP/PFA encapsulation,
which encloses an elastomeric core, completely protecting
it from the media. They combine the energizing properties
of an elastomeric O-ring with the resilience to extreme
temperature and hostile chemicals provided by FEP/PFA
CHEMICAL ENGINEERING WWW.CHEMENGONLINE.COM
APRIL 2024
http://www.vulcanseals.com http://www.trelleborg.com http://WWW.CHEMENGONLINE.COM
che_april-2024

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